The present invention relates to a blind rivet comprising a tubular rivet body in which is mounted a mandrel having a head portion at the narrow end of the stem so that when the mandrel is pulled back in the rivet, it upsets the rivet. When pulling-back of the mandrel is resisted with a predetermined force, the mandrel breaks off. A riveter that operates with such rivets typically has a housing formed at its front end with an aperture through which the rivet mandrel is engaged. Within the housing is a chuck that engages tightly around the mandrel and an actuating mechanism or pulling head which pulls the chuck backwardly, thereby upsetting the rivet and breaking off the mandrel.
In rivet setting machines, the operator sets a rivet held in the nose of the rivet tool by pulling a trigger. The remaining spend mandrel is drawn through the tool and through a collection tube into a collection box. A proximity switch senses the spent mandrel just before it enters the collection box.
There are a variety of different types of tools, both manual and powered, that are used to set pull-type blind fasteners. For industrial production, it is desirable to use a power tool that may have an air/hydraulic or electrical power assist to pull the mandrel stem. This facilitates the rivet setting operation.
It is known to automate the process of feeding rivets to the riveter tool, as for example shown in U.S. Pat. Nos. 6,240,613, 4,754,643, and 4,747,294, commonly assigned. It is also known to automate the mandrel collection process as taught, for example, in U.S. Pat. No. 4,972,985, also commonly assigned. The most common approach to automatic rivet feed and disposal uses hydraulically or pneumatically powered mechanisms for guiding blind rivets to the riveting tool and extracting broken off mandrels therefrom.
Common shortcomings of prior art apparatus for auto-feeding of rivets to the riveting tool is the potential of such systems to leak hydraulic fluid during maintenance, service and change-over. In addition, ways are constantly being sought which speed up the set-up capabilities as well as speeding up the rivet setting process.